From climate change to molecular response: redox proteomics of ozone-induced responses in soybean

Ozone (O3) causes significant agricultural losses, with soybean (Glycine max) being highly sensitive to this oxidant. Here we assess the effect of elevated seasonal O3 exposure on the total and redox proteomes of soybean. To understand the molecular responses to O3 exposure, soybean grown at the Soybean Free Air Concentration Enrichment facility under ambient (37 ppb), moderate (58 ppb), and high (116 ppb) O3 concentrations was examined by redox-sensitive thiol labeling, mass spectrometry, and targeted enzyme assays. Proteomic analysis of soybean leaf tissue exposed to high O3 concentrations reveals widespread changes. In the high-O3 treatment leaf, 35 proteins increased up to fivefold in abundance, 22 proteins showed up to fivefold higher oxidation, and 22 proteins increased in both abundance and oxidation. These changes occurred in carbon metabolism, photosynthesis, amino acid synthesis, flavonoid and isoprenoid biosynthesis, signaling and homeostasis, and antioxidant pathways. This study shows that seasonal O3 exposure in soybean alters the abundance and oxidation state of redox-sensitive multiple proteins and that these changes reflect a combination of damage effects and adaptive responses that influence a wide range of metabolic processes, which in some cases may help mitigate oxidative stress.